August sttndh



INVENOR.

f TToRNE s.

Hlllll A Feb. 3, 1931.

rammed Feb. 3, 1931 AUGUST sUNDn, or HArrNGs-UroN-nnnson, NEW Yom:

SELF-HOLDING DEVICE FOR NUTS Application led September 12, 1928. Serial No. 305,370.

Tn an application filed by the present appllcant on March 17, 1928, Serial N o. 262,381 there is disclosed and claimed a self-holding device for nuts in which a wrapped spring.

Y whereby the spring will be turned upon further movement of the nut. The present invention, while embodying some of the characteristics of the aforesaid self-holding device, diifers therefrom primarily in that the holdingforce is wholly dependent on the physical and dimensional characteristicsof the spring. n

Theprincipal object of the present invention is to provide in a nut self-holding mechanism therefor which is ofsimple construction, inexpensive to manufacture -and assemble and particularly suitable for association with smally nuts. In accordance with the invention there is provided a yielding pressure element and a separate metallic spring element which directly engages the threads of the bolt and is subj ect to the contractive force .of the first-named element which surrounds it. The yielding pressure element may be either metallic or non-metallic but it is so related to the gripping spring element as to urge it yieldingly into engagement with the threads of the bolt with a .force sutlicient to hold the nut against accidental displacement i thereon.'

In the preferred form of the iigvention there is provided a hardened and tempered singleocoil pressure spring one end of which c is anchored in the nut and the other of which isfree and within which is disposed a Isingle coil soft spring which is suliiciently pliable to conform to the inner .periphery of the outer hardened spring and to engage the threads of the bolt intimately with a frictional contact without, however, injuring them. One end of the gripping element is also anchored in the nut, the other end being free. With, such a disposition it will be evident that the holding force is dependent on the characteristics -of the hardened pressure spring taking into account also the dimensional relationship existing between the hardened spring and gripping element when assembled and the diameter of the bolt to v'which the nut is applied. These factors can be so controlled int e design as'to insure a predetermined frictional grip'when the nut is on the bolt. On the other hand, the design issuch that no great precision is require'd in the manufacture or assembly of the parts, the relatively soft gripping element being of such a nature as to adapt itself automatically to the encircling spring element and to the bolt threads.

v Reference is now to be had to the accompanying drawings for a clearer understanding of diiferent embodiments of the invention wherein: l

Figure 1 is a view in section showing a nut having the. improved device incorporated therein, when applied to a bolt.

Figure 2 is a transverse sectional View through the nut and bolt shown in Figure 1 and taken. on-the plane in'dicated by the line 2--2 of Figure l and lookingin the direction of the arrows. i

Figure 3 is 'a view of the exterior of the nuil shown in Figures 1 and 2 and illustrating the spring anchorage therein.

Figure 4 is a sectional view of a modilied embodiment wherein the soft gripping elements are plural in number.

Figure 5 is a -view vin transverse sectionA through a nut having a different form of pressure element surrounding the soft gripping spring. l

Figure is a view in perspective of the plural gripping springs shown in Figure 4.

The nut a is provided with a cavity a at `one end to receive the elements of the im.-

proved self-holding mechanism which comprise generally an outer holding spring Z1 and an inner spring c to grip the threads of the bolt d. In the preferred embodiment the spring\b will be of hardened and tempered will be advisable to bevel its entering end as 10 indicated at c and in such a case, for struc-' l tural reasons, it may be preferable to make the spring c a -little wider than the outer spring. b, as illustrated in Figure l. At all events,"the inner ends of the springs b, c, will rest on shoulders in the cavity a and the outer ends will be engaged by a circular retaining plate e which may be secured on the ends of the nut by turning over a circular iange a2 or by any'ot-her suitable expedient. By the construction described the springs b and 0 are held positively against longitudinal displacement within the cavity.

The .wall of the cavity may be slotted as at a3 to receive one end of the spring b and the corresponding end of the gripping spring c.

These springs when assembled are nested and4 each'of 'a single coil the free ends thereof being spaced from the ends which areanchored in the slots a3 as shown clearly in Figure 2. The anchorage provided holds the two springs iixedly in relation .to the nut so that bodily movement of the springs is-prevented positively regardless of the direction of turning of the nut.

The strength of the pressure springbcan be predetermined to meet` the required conditions, its function being to press the inner gripping spring c into engagement with the threads of the bolt b with such force as may be most effective to hold the nut against accidental movement along the threads up to a predetermined point. The spring c is suiciently pliable to conform to the inner surface of the spring b so that it receives uniformly the contractive holdin force impressed thereon bythe spring b. ts hardness is such also as not to injure the threads of the bolt when the parts are threaded thereon. The springl b, of course, rests loosely Within the cavity a so as to be capable of vexpansion toa necessary degree -to permit entry of the bolt into the spring c. The relative dimensions of the springs b and c and the diameter of the cavlty and t 1e diameter of the bolt are also all factors which will influence the holding force impressed on the threads of the bolt, as will be apparent.

When the nut shown in Figure 2 is turned in a clockwise direction to thread it on to the bolt the free ends of the springs b, c, will tend to leave the threads so that the resistance offered is a minimum. If, however, the nut tends to turn in a counterclockwise direction so as to unthread itself the ends of the springs tend to wrap down on the threads and exert maximum resistance. The maximum holding force, however, is determined by the factors hereinbefore discussed and when it has been exceeded the parts will move along the threads as is desirable when the nut is to be removed with the wrench. The free ends of the springs cannot contact with the anchored ends so no positive or mechanical relief is 05 afforded when the nut-is turned o.

variance of the holding force the inner spring c may have substituted therefor a plurality ,of relatively narrow elements f any one or all of which may be removed or replaced.

In Figure 5 the inner gripping element may be formed as the spring c heretofore described but in place of the outer holding spring b there has been substituted a different form of holding spring indicated at g which may be formed as a flat spring having plural reverse bends. This spring is compressed within the space between the wall ofthe cavity and the gripping spring o. When the bolt is threaded throughfthe nut the spring c will be expanded but such expansion will be opposed yieldingly by the spring g and in that way a holding force of predetermined, amount is impressed on the threads to prevent displace ment of the nut. When the nut is removed from the bolt the holding spring will resume its normal set.

.Changes in the construction which are related wholly to matters of design may be made by one skilled in the art without departing from the invention.

What I claim is:

1. In a nut having a threaded portion and a cavity, the combination of a holding de'- vice disposed in the cavity and engaged with the nut to rotate' therewith, said holding device comprising an inner metallic spring ele-l ment adapted to engage t-he bolt threads frictionally and la resilient pressure element secured to the nut4 to rotate therewithand cooperating with the spring element to urge it in frictional contact with the threads.

2. In a nut having a threaded portion and a cavity portion, a holding device ,in the cavity portion engaged with the nut to rotate therewith and comprising a singlecoil hardened and tempered spring in the cavity and a soft spring element in the cavity`nested in the first namedspring to engage the bolt threads, said soft spring element being urged into frictional contact therewith by the outer spring element.

4. In a nut having a cavity therein the combination of a single coil spring having one end anchored to the nut to turn therewith, a soft single coil spring nested in the cavity in the first named spring and 4having one end rigidly anchored to the nut to turn therewith, said inner spring engaging the `bolt threads ipo and maintainedin frictional contact there- ,i l with by the outerspring element.

5. In a nut having a cavity therein the combinatio'n of a singlecoil spring having one i end anchored. to the nut to.turn therewith,

a soft single coil spring nested in the first named spring and having one end rigidly anchored to the nut to turn therewith, said inner spring 4en aging the bQlt threadsrand maintained in rictional contact therewith by the outer spring element, and means carried with the nut at the end of the cavity portion to maintain the spring elements against longitudinal displacement.

6. Ina nut having a threaded portion and a cavity portion, a holding device in the cavity portion, comprisin a 4single coiled spring of'wider material t an the width of the thread grooves in the threaded portion,

'20 and of softer material than the thread on nthe bolt and held with one end rigidly anchored to the nut to rotate in unison therewith, and a spring pressure device positively held in position relatively tothe first named spring within the cavity to press it into frictional contactwith the bolt threads. r

7. Ina nuthaving athreaded portion and a cavity portion, a `holding device in the cavity portion engaged with the nut to rotate therewith and comprising a single coil spring through which the bolt passes and a spring .within the cavity encircling the inner spring and in nested rel tion therewith to urge the vinner spring in ictional contact with the bolt threads, the free ends of the `coils being so disposed with respect to the bolt as to exert minimum holding force when the nut 1s turned in one` direction and maximum holding force when the nut is turned in the oppo- 4.0 site direction.

Y -4.5 having a width equal at leastto the 00mg' A v 8. In a nut having a threaded `portion and a cavity, 'a plurality of gripping springs disposed m'juxtapo'sition within the cavity-to: engage the .threads of a bolt, a pressure s me a width of the gripping springs di osed 011tside of and in nested relation to'sai gripping springs, the cavity being of such cross sec-l ,tional area as to permit circumferential ex- .p 5o pansion of the pressure and gripping 4springs -whenlthre'ade onto the boltand means to hold all of said springs against longitudinal displacement within the cavity.

This specification signed this 7th day of la", september, A. D. 192s. 

